Guitar Chemistry

Anyone for a cocktail?

It's time to start mixing up some liquids in the lab!  

It's funny - if you are doing all the steps yourself - Luthiery includes Math, Chemistry, Woodworking, Electronics, Music, Art, History and a dash of Engineering.  It's like an entire high school curriculum in one.

There are many ways to finish a guitar: varnish, mineral oils, shellacs, lacquers, etc...

And those are just the top coats - the protectants for after you've dyed, stained, or painted your guitar.

The list goes on and on.  

I am planning on dying the top (the maple parts) and using shellac and nitrocellulose lacquer on the rest of the guitar.  The shellac will deepen the color I dye the maple, really make the wood figure of the butternut "pop," and it will also allow the nitrocellulose lacquer to bond to the cocobolo (and it will make the cocobolo look good too).  The Nitro will protect the wood from temperature and humidity changes while also protecting the wood from impact damages and my bodily secretions...

...get your mind out of the gutter.  My sweat!  Sweat and skin cells can stain wood all kinds of weird colors.  So, we protect the wood.  How?  Let's start with the Shellac.

Flaky

Shellac is a natural substance that comes from lac bugs.  I want to know what madman first realized you could take what looks like a bug cocoon and mix it with alcohol to make wood varnish.  You'll note the word "alcohol" is in that sentence...

Anywho, shellac comes as a pre-made liquid (in cans and sprays) but it also comes as raw flakes.
You add denatured alcohol to the flakes to make your own mixture.
I won't go into excruciating detail but the amount of flakes you add to the alcohol changes the strength or "cut" of it.  For this Guitar I am using a 2 pound cut.  If I was not going to use nitro over the shellac I would use a 3 or 4 pound cut - essentially adding more flakes to make a more viscous shellac.  But I'm essentially using the shellac as a colorant and grain enhancer and not the top coat - so it can be thinner.

Shiny, Captain

I like to use a sealable jar as I won't be using the shellac right away and it does take a while for the flakes to completely dissolve in the alcohol.  Also, seeing as the major solvent in shellac (alcohol) evaporates kinda easy - it just makes sense to me to cover it when I'm not using it.

Uh, muddy, Captain

I'll let this mixture sit for a day or two to fully dissolve the flakes and by the time I'm ready to use it - it'll be ready to go.  A few thoughts:  All kidding aside - don't use vodka to dissolve the shellac flakes.

Use denatured alcohol.   Stir, shake, or mix the shellac every now and then to help the process along.

Finally, I'm running the mixture through a paint strainer before using it on the guitar.  This stuff comes from nature (tree bark, dirt, and bug body parts included).  Any paint store will have strainers.

So, let's let the shellac sit for a bit and move on to dyes.

Should I be making a Trans joke?
Nope, I should not.

Because I'm going to be dying the maple on the top of the guitar and not staining it (and I have no idea what exact tint I should use) I'm going to make my own hue.  Or is it shade? Art class was so long ago.

For those of you wondering what the difference is between using a wood stain and using a wood dye we turn to Alan Noel, wood worker and teacher.  Quoth Alan, "Very simply put, stains are very thin paints and dyes are why your socks are red out of the washer. With stains, the pigment tends to remain on the surface of the wood and lodge in the pores, while dyes penetrate deeply and color the wood from within."

I'm using TransTint dyes for this project.  TransTint is super super concentrated dye in a liquid form. TransTint is neat stuff because it can be mixed with water, alcohol or even mixed with shellac or nitro - it's pretty versatile. Since this is my first time out with it I am doing some test strips.  I have two colors to work with: Black and Coffee Brown.

Mmmmmm.  Coffee...

In my last post I talked about trying to use real coffee to stain/dye the maple.  It didn't work out that well. One of the biggest issues being that it dries too light and because it's water based it raised the grain every time I applied a new coat of color.  So, I scrapped that idea but I still wanted the coffee color for the guitar.  The dye will go on darker and because I'm using alcohol as the solvent - it won't raise the wood grain.  The reason why I bought the black pigment is to make the color richer - but probably not how you think...

The above picture is a mixture of probably an 1/8 to a 1/4 of a cup of alcohol and maybe 4 or 5 drops of the Black TransTint dye.  Like I said - super concentrated.

I feel so naked...

I still had a scrap of maple that came from the same board the guitar top is made from.  I sanded it down with 220 grit sandpaper and hit it with one coat of the dye.

Thank you, that's much better.

It looks a little purple in this photo but it dried gray (grey?).  You can see some of the maple "flame" in the above picture.  The dye sticks to the flame more than the non-flamed parts of the wood.  That'll be important later.  I wasn't satisfied with this - so I hit it a few more times with the black dye.

Too far!  Now I'm overdressed.

The flame or figure is pretty hidden right now.  Although a good coat of shellac would still probably make it pop quite a bit.

Everything is Brown!

Then I turned the scrap over and did the same thing but with the Brown dye.  This time the camera made it look a bit more red than it is - but I have mixed lighting in my workshop - so who knows what's going on.  Then after all this coloring we act like a 1st grader and erase everything and start over.

Black - Naked but unafraid

The key here is to remove all of the dye except the stuff that's in the "flame" or figured part of the wood.  So I sanded the color most of the way off on the Black side...

Brown - feelin' worn down

And the Brown side.

Then I mixed up a 1/4 cup of the brown dye again and hit both sides of the scrap.  

And this is what we have:

First coat Black, second coat Brown

First coat Brown, second coat Brown

...and that's pretty frickin' subtle...

Did that even work?

Okay full disclosure - there's more going on here than at first glance.  After I did the second coat of dye I let them dry and hit them both with a coat of the Shellac (remember the shellac we made all the way at the beginning of this post?).  The shellac is making them both look fabulous but they are also pretty shiny and hard to photograph.  Since it's not easy to see - what's supposed to happen is the black gives the flame more depth - making it look more three dimensional.  And it does...

...a bit

...but only when you tilt the wood back and forth

...which is hard to show with a picture.

...maybe it's time to switch to video...

But really, they both look pretty sexy - and this is just scrap that I haven't sanded (or photographed well). If I had chosen a lighter brown (or any lighter color, really) the flame would probably pop a bit more because of the black.  I'm going to lightly "finish" sand them both and see what looks better.  But I think either process would work for what I want.  So, I guess this was a successful test.  I now know that either will work well.  Time will tell which will work out better.